INTRODUCTION. Ai-Hua Liu 1, 2, Yan-Hua Lin 1, Min Yang 1, Jiang-Hao Sun 1, Hui Guo 1, De-An Guo 1, 2 *

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1 High-performance liquid chromatographic determination of tanshinones in the roots of Salvia miltiorrhiza and related traditional Chinese medicinal preparations Ai-Hua Liu,, Yan-Hua Lin, Min Yang, Jiang-Hao Sun, Hui Guo, De-An Guo, * The State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing P. R. China Shanghai Research Center for TCM Modernization, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China Received July 8, 005; Revised November, 005, Accepted November, 005, Published December 9, 005 ABSTRACT Purpose: This paper describes a validated high-performance liquid chromatographic method to quantitate four tanshinones as markers; dihydrotanshinone I, cryptotanshinone, tanshinone I and tanshinone IIA for use in the quality control of the roots of Salvia miltiorrhiza and its related traditional Chinese medicinal preparations. Methods: Separation was achieved using a Zorbax Extend C8 reserved-phase column (5µm, 50.6mm) at 0 C with a gradient mixture of deionized water and acetonitrile at a flow rate of.ml/min. Result: The limits of quantitation were 0., 0.08, 0.06 and 0.05µg/ml for dihydrotanshinone I, cryptotanshinone, tanshinone I and tanshinone IIA, respectively. This method provided good reproducibility and sensitivity for the quantification of four tanshinones with overall RSD values for intra-day and inter-day precision and accuracy better than.8% and higher than 9.9%, Corresponding author: De-an Guo, The State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, No.8 Xueyuan Road, Beijing 0008, P. R. China. gda@bjmu.edu.cn respectively. The recovery of the method was % for all the tanshinones and showed good linearity (r>0.9998) over a relatively wide concentration range. Conclusions: This assay was successfully applied to the determination of four tanshinones in the roots of Salvia miltiorrhiza and its related traditional Chinese medicinal preparations. The results indicated that the HPLC assay could be readily utilized as a quality control method for the roots of Salvia miltiorrhiza and its related traditional Chinese medicinal preparations. INTRDUCTIN The roots of Salvia miltiorrhiza (Danshen), a commonly used herbal medicine in China, are widely used to treat coronary heart disease, cerebrovascular disease, hepatitis, hepatocirrhosis and chronic renal failure (-). Due to its purported biological activity and fewer side effects as confirmed by pharmacological investigations and clinical use, many traditional Chinese medicinal preparations (TCMPs) containing Danshen, such as Fufang Danshen tablets (FDT), Compound Danshen Dripping pills (CDDP), Danshen injection (DSI) and Xiangdan injection (XDI), have been developed. These TCMPs are mainly used to treat coronary heart disease, heart-stroke, and associated cerebrovascular and cardiovascular diseases (5-9). To ensure clinical efficacy, quality control of Salvia miltiorrhiza and its related TCMPs is critical. Since Danshen is the major component of FDT, CDDP, DSI and XDI, quality control of Danshen content is thus essential to guarantee the quality of these TCMPs. Tanshinones are hydrophobic components isolated from Danshen. It has been reported that tanshinones possess anti-toxin properties, modulate immunological diseases, dilate coronary arteries, increase coronary flow and protect the myocardium against ischaemia (0-). In addition, tanshinones have attracted particular attention because they have exhibited significant

2 antibacterial, anti-dermatophytic, anti-neoplastic and anti-platelet aggregation activities (-6). In the Pharmacopoeia of the People s Republic of China (005 Edition) (), quality control of Danshen and FDT has relied mainly on the determination of tanshinone IIA. A number of studies on the quantitation of tanshinones in Danshen and its related TCMPs by thin layer chromatography (TLC), spectrophotometry or HPLC have been reported. However, only a few tanshinones were determined in these papers (7-). According to the literature () and our study, dihydrotanshinone I, cryptotanshinone, tanshinone I and tanshinone IIA (Fig. ) are the main tanshinones contained in Danshen and its related TCMPs. Figure : The structures of selected tanshinones:, dihydrotanshinon I;, cryptotanshinone;, tanshinone I;, tanshinone IIA Therefore simultaneous determination of these four tanshinones could, to some extent, reflect the overall quantity of Danshen and its related TCMPs. In this report, we describe a simple, rapid and accurate method of analysis using reversed-phase HPLC (RP-HPLC) to simultaneously determine dihydrotanshinone I, cryptotanshinone, tanshinone I and tanshinone IIA in Danshen and in four TCMP samples. MATERIALS AND METHDS Chemicals and Materials HPLC grade acetonitrile and methanol (E. Merck, Darmstadt, Germany) were used for the HPLC analysis. Deionized water was purified by a Milli-Q system (Millipore, Bedford, MA, USA). Phosphoric acid and chloroform were of analytical grade from Beijing Beihua Fine Chemicals Co., Ltd. (Beijing, China). The roots of Salvia miltiorrhiza and TCMPs samples were purchased from drugstores around China (Table ). Dihydrotanshinone I [], cryptotanshinone [], tanshinone I [] and tanshinone IIA [] were purchased from the National Institute for Control of Biological and Pharmaceutical Products of China, and their purity was over 98% by HPLC analysis. Apparatus and chromatographic conditions An Agilent 00 HPLC system (Agilent Technologies, Palo Alto, CA, USA) comprising a quaternary solvent delivery system, an on-line degasser, an autosampler, a column temperature controller and photodiode array detector coupled with an analytical workstation was used. The column configuration was an Agilent Zorbax Extend C 8 reserved-phase column (5µm, 50.6 mm) with an Agilent Zorbax Extend C 8 guard column (5µm, 0.6mm). The sample injection volume was 0 μl. The detection wavelength was set at 70nm, the flow rate was.ml/min and the column temperature was maintained at 0 C. The mobile phase consisted of A (deionized water) and B (acetonitrile). Gradient elution was as follows: Initially 5% B at 0 min, linearly increasing to 60% at min, maintaining 60% B from min to min, linearly increasing B to 80% at 5 min and then linearly increasing B to 8% at 0 min until the end of the run. After each analysis, 5% mobile phase B was pumped and maintained for 0 min to re-equilibrate the system for baseline stability. An SB 500 ultrasonic generator (50 KHz, 50 W) from Shanghai Branson Ultrasonics Co. Ltd (Shanghai, China) was used to aid the extraction of tanshinones from the samples.

3 Table : Calibration curves of tanshinones. Retention Time Analyte (min) Standard curve r Test range (µg ml-) LD (µg ml-) LQ (µg ml-) Dihydrotanshinone I 8.0 Y=.x Cryptotanshinone.95 Y=6.85x Tanshinone I. Y=0.09x Tanshinone II A 8. Y=.0x Y: peak area; x: concentration of analyte (µg ml - ) An FW00 pulverizer (000 rpm/min, 60 W) from Tianjin City Taisite Instrument Co. Ltd (Tianjin, China) was used to comminute the Danshen. Quantitative filter paper (No.0, 9 cm) supplied by Hangzhou Fuyang Special Industry Co., Ltd (Hangzhou, China) and the membrane filters ( mm, 0.5 μm) were obtained from Tianjin Tengda Filtration Instrument Co., Ltd (Tianjin, China). Preparation of calibration standard solutions A methanol stock solution containing compounds,, and was prepared and diluted to the appropriate concentration range (Table ) for the establishment of calibration curves. Each calibration curve was analyzed three times with six different concentrations using the same HPLC conditions as described above. Sample preparation The dried roots of Salvia miltiorrhiza were sheared to be about cm in length and then comminuted by pulverizer. After the coating was removed by abrasive cloth, FDT and CDDP were ground in a mortar. Each solid sample (00 mesh, 0.00g) was suspended in methanol: chloroform (7:, v/v, 0 ml) and sonicated for 0.5h. After filtration, the filtrate was transferred to a 5 ml volumetric flask and evaporated to dryness at 8 C. The evaporated residue was dissolved in methanol and made up to volume in a 0 ml volumetric flask. ne milliliter of either DSI or XDI liquid sample was diluted to 6 ml with deionized water. The solutions were filtered through a membrane filter (0.5 μm) and then injected into the HPLC. Quality control samples n different days, QC samples containing the relevant reference compounds (low, medium and high concentrations) were used to verify the calibration curve. The calibration curve could be used on subsequent days when the coefficient of variability (CV) of the QC samples was less than %, failing which a new calibration curve would be established. Precision and accuracy The measurements of intra-day and inter-day variability were utilized to determine the precision of the method. Three different concentrations (low, middle and high) of the four standards were prepared. The relative standard deviation (RSD) was used as a measure of precision. The intra-day variability was examined within one day (n=5) and inter-day variability was determined in triplicate on separate days. Recovery experiments were carried out by spiking FDT (0.5g, brown powder ) with different amounts (low, medium and high) of authentic standards with known contents of marker compounds and the samples were treated according to the sample preparation procedure. Limits of detection (LD) & limits of quantitation (LQ) LD is defined as the lowest amount of analyte which can be detected. It is formally defined as X-X B =S B, where X is the signal from the sample, X B is the signal from the analytical blank and S B is the SD of the reading for the analytical blank (6). LQ is the lowest amount of an analyte which can be quantitated and similar to LD, LQ is formally defined as X-X B =0S B.

4 RESULTS AND DISCUSSIN ptimization of Extraction Procedure and Chromatographic Conditions In order to achieve quantitative extraction, variables involved in the procedure such as solvent, extraction method and extraction time were optimized. A series of solvents such as methanol (MeH), methanol:chloroform (CHCl ) (7:, 5:5, :7, v/v) and CHCl were tested as the extraction solvents of tanshinones (-5). The best solvent was found to be a mixture of MeH: CHCl (7:, v/v) (Table ), which allowed extraction of all the tanshinones in high yield. MeH or CHCl alone were not efficient for the complete extraction of the four compounds of interest. Table : Comparison of different extraction solvents. Extraction Solvent The peak area of tanshinones MeH MeH :CHCl =7: MeH :CHCl =5: MeH :CHCl =: CHCl The ultrasonic treatment procedure was found to be the best extraction method for the tanshinones. In order to investigate extraction time, powdered FDT (0.00g) samples were extracted with 0 ml MeH: CHCl (7:, v/v) for 0, 0, 0, 5, 60 min, respectively. The results suggested that all the tanshinones were almost completely extracted within 0 min (Table ). Table : Comparison of extraction time. Extraction Time The peak area of tanshinones 0 min min min min min Therefore, the optimal extraction method of tanshinones was ultrasonic extraction with 0ml of the mixture of MeH: CHCl (7:, v/v) for 0 min. A good separation is assumed when the analyzed peaks are baseline separated within a short analysis time. To obtain chromatograms with good separation, various stationary phases, mobile phases, column temperatures, detection wavelengths and flow rates were investigated. For the assay of tanshinones in Danshen and its related TCMPs, a Zorbax Extend C8 was found to be better than BDS-Hypersil C8, YMC-Pack DS-A C8 or Luna C8. Various mixtures of water/acetonitrile or water/methanol were used as mobile phase and the results indicated that water/acetonitrile system was better than that of water/methanol. Due to the similar retention behaviors of compounds and, the mobile phase B (acetonitrile) was maintained at 60% from min to min to achieve a baseline separation of these two compounds. It was also found that the best separation was achieved when the column temperature was kept at 0 C using a flow rate of.ml/min and detection wavelength of 70 nm. Linearity and range Figure shows a typical chromatogram of four tanshinones,,, and with retention times 8.0,.95,. and 8. min, respectively. Fig. : Representative HPLC chromatograms of (A) standard solution at medium concentration, (B) FDT (Xianzhi,Liaoning, China), (C) Danshen (Shanxi, China), dihydrotanshinon I;, cryptotanshinone;, tanshinone I;, tanshinone II A. A B C

5 Table : Intra-and inter-day variability. Inter-day (n=9) Intra-day (n=5) Concentration (µg ml - ) Found RSD a (%) Accuracy b (%) Found RSD (%) Accuracy (%) Dihydrotanshinone I ± ± ± ± ± ± Cryptotanshinone.75.0± ± ± ± ± ± Tanshinone I ± ± ± ± ± ± Tanshinone II A ± ± ± ± ± ± a RSD(%) = (SD/mean) 00 b Recovery(%) = (mean of measured concentration/spiked concentration) 00 Table 5: Recoveries of the four tanshinones (n=). tanshinone spiked (µg ml - ) Found (µg ml - ) RSD a (%) Recovery (%) Dihydrotanshinone I.0.9± ± ± Cryptotanshinone ± ± ± Tanshinone I ± ± ± Tanshinone IIA ± ± ± a RSD(%) = (SD/mean) 00, b Recovery(%) = (mean of measured concentration/spiked concentration) 00 5

6 The four peaks in the samples were monitored in the UV range from 00-00nm with a DAD-detector and assessment of peak purity showed peak homogeneity thereby indicating the specificity of the method. Linear ranges and correlation co-efficients are depicted in Table. All the standard compounds showed good linearity (r>0.9998) in a relatively wide concentration range. System suitability The intra-day precision is shown in Table where the RSDs ranged from 0.% to.0%. The inter-day precision was determined from nine determinations over separate days for each concentration and the results were in the range of.00%-.80%. The recovery of the four standards ranged from 95.% to 0.% (Table 5). Stability testing was performed on a sample solution left on the bench and was analyzed every h over days at room temperature. The analytes were found to be relatively stable over 7 h (RSD<5%). LD and LQ The LDs of the four tanshinones were 0.05, 0.0, 0.0 and 0.0 μg ml and the LQs were 0., 0.08, 0.06 and 0.05 μg ml, for,, and, respectively (Table ). Sample analysis Forty samples were prepared as previously described. A volume of 0 μl of filtered solution of each sample was injected into the instrument and each sample was determined in triplicate. Peaks in the chromatograms were identified by comparing their retention times and on-line UV spectra with those of the reference standards. The method was successfully applied to determinate four tanshinones in Danshen and in four Danshen-containing TCMPs, FDT, CDDP, XDI and DSI, respectively. The contents of the four major tanshinones in 0 samples are shown in Table 6. From Table 6, it is obvious that the quality of fourteen Danshen samples from different locations varied quite drastically and could account for uncertain and unstable curative effects of the TCMPs. Furthermore, it can be seen that the contents in four of the TCMPs also varied markedly and are hardly detectable in DSI and XDI, low in content in CDDP and high in Danshen and FDT samples. The reason for the variation might be due to different processing procedures of Danshen during the manufacturing process. It is also obvious from Table 6 that the contents of the tanshinones in FDT varied greatly amongst the different manufacturers. The variation of contents may be due to different quality of the raw material, the difference of production procedure, storage and transportation, etc., amongst others. In the Pharmacopoeia of People s Republic of China (005 Edition), tanshinone IIA is claimed to be present in not less than 0.% of Danshen crude drug and 00μg/tablet for FDT. In our samples of Danshen crude drugs analyzed, there are samples (N0s.,, and 7-) that meet the specified standard by Chinese Pharmacopoeia, while all FDT samples determined meet this standard. Considering the purported medicinal properties of tanshinone I, crytotanshinone and dihydrotanshinone I, it is recommended that not only tanshinone IIA but also tanshinone I, crytotanshinone and dihydrotanshinonei should be determined for use as quality control markers for Danshen crude drug and TCMPs containing Danshen. CNCLUSINS This paper describes a simple, accurate and precise method for the simultaneous determination of the four major tanshinones in Danshen, FDT, CDDP, DSI and XDI. The data obtained from 0 samples reveal that the contents of tanshinones in Danshen and FDT varied considerably. The contents are very low in CDDP and almost undetectable in DSI and XDI. The current HPLC method has thus been shown to be suitable for use as a method for the quality control of Salvia miltiorrhiza and its related TCMPs to assure their clinical efficacy. 6

7 Table 6: Contents of tanshinones in samples of Danshen and its related TCMPs. Content f (n=) N Batch Number or harvest time h Collection Province Tanshinone IIA Tanshinone I Cryptotanshinone Dihydrotanshinone I a 090 Guangdong 57.±9. 9.5±9.0.±8. 5.9±5.9 a 07 Beijing 5.± ± ±..0±6. a 070 Shenzhen 5.6±6..± ±5. 9.9±. a 0 Guangxi 5.5±. 87.±. 9.6±.6.5±. 5 a 00 Henan 7.± ± ±6. 70.±.6 6 a 999 Hebei.6± ±.7 7.5±. 8.±. 7 a 000 Anhui 696.6± ±.5 8.6± ±.5 8 a 07 Shanghai 6.5±9. 9.6± ±.6 8.6±9.7 9 a 069 Beijing 8.±9. 85.±9.5.±..±6. 0 a Yunnan 666.± ±6. 7.± ±6.7 a 06 Sichuang 609.±.5 5.± ± ±. a Hebei 7.±.5 0.7±. 5.5±..±.7 a 00 Fujiang 9.±.5.8± ±6. 75.±. a 0505 Guangxi 6.6±5. 9.±6. 5.± ±.8 5 a 00 Jiangxi 507.±6. 7.5±. 69.6±,5 8.8±. 6 a 0 Guangdong 675.5±.6.±6. 00.±6. 87.±6. 7 a 0 Guangdong 576.±5..6±6.6 7.±.0 ND 8 a 008 Guangdong 777.±.5 6.8±6. 6.±6. 5.5±.6 9 a 0900 Guangdong 65.±. 08.± ± ±6. 0 a 07 Beijing 58.±7.5 5.±9. 50.±9.7.5±6. b 0006 Shandong.0±0.09.8±0.0.6±0.0.7±0.0 b 0007 Sichuang 5.0±0.7.±0.0.08±0.05.7±0.0 b 0008 Shanxi 7.5±0..0± ±0.05.5±0.0 b 0009 Liaoning 0.± ±0.0 0.± ± b 0009 Henan.79±0.08.6± ± ±0.0 6 b 0008 Zhejiang 0.0± ± ± ± b 0007 Shanxi.±0..0±0.0.8±0.0.95±0.0 8 b 0009 Liaoning.7±0.0.7±0.0.59±0.0.±0.0 9 b 000 Henan.5±0..09±0.0.5±0.0.±0.0 0 b 0008 Shanxi.0±0.09.± ± ±0.0 b 0007 Hebei.8± ±0.0.9± ±0.0 b 000 Shanxi.7±0.08.0±0.0.9± ±0.0 b 000 Shanxi.60± ±0.0.8±0.0.05±0.0 b 000 Shandong 5.±0..9± ±0.0.±0.0 5 c 0070 Shanghai ND ND ND ND 6 d 0088 Guangdong ND ND ND ND 7 e 0000 Tianjing ND.8±0. 5.±0. ND 8 e Tianjing ND.9±0. 5.5±0.5 ND 9 e 0008 Tianjing ND.7±0. 5.±0. 5.±0. 0 e Ttianjing.7±0..7±0. 5.±0. 5.±0. a : Fufang Danshen tablet, b : Danshen crude drug, c : Danshen injection, d : Xiangdan injection, e : Compound Danshen dripping pill, f Content = mean±sd(n=), units of Danshen crude drug is mg/g, units of FDT is µg(tanshinone)/00mg tablet, units of CDDP is µg(tanshinone)/7mg dripping pill, units of DSI and XDI is mg/0ml injection, g ND: not detected, h : Batch Number used in the TCMPs and Harvest time used in Danshen crude drug. ACKNWLEDGEMENTS We thank the Ministry of Science and Technology of China (00BA906A, 00DEA 00 and 00BAC0A56) and National Administration of Traditional Chinese Medicine (00ZX0) for financial support. 7

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